Single staged taumel gear reduction units are well known in the art. Such reduction mechanisms take advantage of the wobbling of an off-centered gear within a housing, the off-centered gear and the housing having compatible teeth disposed upon their engaging surfaces. Typically in a taumel gear arrangement there exists between the center gear and the housing at least one tooth difference, that is to say that the centered gear has at least one less tooth than the teeth disposed upon the housing. Thus, the off-centered gear is free and under no constraint to rotate at the same speed as an input shaft driving it about the housing. Conventionally, the drive shaft engages a cam which as a result of its eccentricity further engages the centered gear which wobbles about the housing. The relationship between the number of teeth upon the housing and the number of teeth upon the centered gear is defined thereby providing a ratio of the speed reduction available when using the taumel principle. For example, if a ring gear had 51 teeth and the central gear had 50 teeth, the output speed of the central gear as it wobbled about the ring gear would be a 50 times reduced speed to that of the input speed provided. A pin coupling may be used to transmit the rotation of the central gear.
U.S. Pat. No. 3,401,979 by Putsch discloses such a taumel arrangement for use in motor vehicle seats having a toothed ring gear in communication with an externally toothed gear wherein there exists at least a one tooth differential in the diameter of the toothed gear in relationship to the ring gear. An eccentric portion cooperates with the gears in order to move the back rest and adjust its final position. However, the aforementioned patent does not describe an effective dual stage reduction. Further in relation to FIG. 9 as described in column 6 at lines 53 through to 59, a second stage of reduction is provided being considerably more cumbersome than the instant invention.
U.S. Pat. No. 3,423,785 by Pickles discloses a position control mechanism incorporating an eccentric mounting using a rotary friction element which takes advantage of the aforementioned taumel principle in operation. Again, the aforementioned patent does not disclose a dual stage reduction unit, nor does it disclose a motorized version of the alternative embodiments of the aforementioned invention.
U.S. Pat. No. 4,196,931 by Werner discloses a hinge for adjustably mounting a back rest component on a seat having two spur gears which are eccentrically rotatable within the hinge elements but are connected together for joint turning. The patented invention is best understood in relation to FIG. 1 illustrating the common drive shaft extending through the two spur gears 23 and 24 which may have alternative cam surfaces or eccentrics as illustrates in relation to FIG. 4 at items 40 and 41, but nonetheless which rotate upon a common shaft. Referring to column 6 at lines 40 through 56, a full description of the operation of the spur gears in relation to the internal gear annular 14 and 15 is found. However, there is no description of a dual stage reduction as provided in the instant invention. Further, a motorized version is not embodied nor described.
U.S. Pat. No. 4,371,207 by Wilking further describes a position adjuster for motor vehicle seats and windows having two levers with a ring gear mounted on one and a planetary gear mounted on the other having a wedge-like segments urging one into relationship with the other. Again there is an eccentric mounting which provides for the application of the taumel principle embodied in the aforementioned invention. However, again there is no two stage reduction nor is there a powered alternative embodied in a compact fashion for the aforementioned invention.
U.S. Pat. No. 4,469,375 by Boyer discloses a power hinge recliner using the taumel principle but providing merely a single stage reduction using the taumel principle wherein further reduction is provided by a worm and a worm wheel for driving the eccentric cam resulting in a much more complex structure that the instant invention. Referring to FIGS. 1 and 8 which best described the preferred and alternative embodiments of the invention it can be readily seen that a very much complicated device is disclosed which utilized the taumel principle along with the use of planetary and worm gears for use in the reduction of the speed in the first stage prior to the wobbling motion of the taumel gear which ultimately reduces the speed of the input shaft to that which would adjust the seat back to the appropriate position. However, within the instant invention the taumel principle is used in a dual stage reduction unit embodied within a module which has the advantages of fitting within very tight or limited locations, and is considerably easier to mount, fabricate and manufacture.
Nowhere is there found within the prior art a dual stage taumel gear reduction unit which is embodied in a module which provides the reduction of the input speed provided by either a hand or a motorized input through to an output which may be readily used to regulate a window regulator, lock or unlock a vehicle door, or used to adjust the seat back of a vehicle seat. Further, nowhere within the prior art is found a compact package, as found in most hand actuated taumel gear arrangements having a single stage reduction, which provides a dual stage reduction in the speed ratios of an input and an output.
Therefore, it is an object of this invention to provide a dual stage taumel gear reduction module in a compact package.
It is a further object of the invention to provide an economical dual stage reduction unit which is easy to manufacture and reliable in use.
It is a further object of the invention to provide a dual stage reduction module which is sized to fit within limited space requirements as posed by vehicle construction today.
It is still a further object of the invention to provide a flat motor which compatibly integrates with the dual stage reduction unit thereby providing a complete module which may be mounted for use in automotive and non-automotive applications.
It is yet still a further object of the invention to provide a modular powered seat recliner adjuster which meets all of the aforementioned objectives.
Further and other objects of this invention will become apparent to a man skilled in the art when considering the following summary of the invention and the more detailed description of the preferred embodiments illustrated herein.